Optical fiber connectors seek to couple light transmitted in one fiber to another by end-to-end mechanical coupling of the two fibers to form a continuous transmission channel with low insertion losses. One such coupler described in "Low Loss Splicing and Connection of Optical Waveguide Cables" by Robert M. Hawk and Frank L. Thiel, SPIE Vol. 63 (1975) Guided Optical Communications, pp. 109-113, employs parallel rods to retain and concentrically align the end of the fibers to be coupled. Three rods will retain and align one fiber channel, but each rod may retain and align as many as 6 fiber channels in a multi-channel connector.
The cost of optical fiber transmission cable is high. Half-duplex communication systems, i.e., communication in both directions but only one direction at a time, effectively reduces the cost of cable since such a system requires only one fiber per two-way channel. However, such systems also require switches at each end of each channel. Such optical fiber switches should provide (1) precise, positive mechanical stops to achieve consistently reproducible coupling loss; (2) low loss in each position, substantially equal to the loss of a precision optical connector; (3) high isolation between ports; (4) relatively fast switching time; and (5) low cost, at least relative to the optical fiber it replaces.